In your User Control Panel (top right of the screen) under Additional options there are the following settings...
 
Speed Options
 
Don't show smiley faces in posts
Don't show image in posts
Don't show avatars of the posters
Don't show signature of the posters
 
If you check off the last two or even just the last one it will save a lot of space. You don't really need to see everyone's sigs for every post (just remember you have it turned off before yelling at OP about providing system specs... lol) and it does save quite a bit of space. However it's the avatars and the user info under them that tend to take up space on shorter posts. You figured out the Essentials thing which I think gets rid of the info but hiding the avatars save a TON of space. Unfortunately then you no longer have the visual cue that let's you know who you are talking to at a glance.
 
The mobile version is quite a bit more compact too but the navigation sucks.
 
BTW if you switch to essentials on the actual forum topic list page you will not get that little dealymabob that shows you've commented on a thread. IIRC you can have the topic list set to full while having the actual threads set to Essentials. I only played around with that briefly after the update though so maybe I was just getting confused.

What I'd like denser is the list of topics, not the actual contents of a topic.  Disabling the avatars and sigs does not save space in the topic list, and the absence of avatars makes it harder to distinguish posts.
 
On this laptop, I can now see 11 topics per screen.  On a standard phbbb forum, I can see 17.5 posts per screen.  This difference is huge.  Nobody likes having to scroll so much. 
 
Sometimes I think Cakewalk's usability experts left the company long ago, and we're left with a bunch of young designers who think in terms of screen grabs rather than actual use.  What happened to the lean-and-mean Cakewalk aesthetic which placed usability over beauty? 
 
I mean, really: What the heck happened to Cakewalk between Sonar 8.5.3 and X1?  Their whole philosophy changed, and I for one have yet to appreciate the "new" Cakewalk.  I wish some old-timers would rejoin the Cakewalk team, or at least speak up more in meetings. 
 
Give us back our usability, Cakewalk.  Stop focusing on the f---ing screen grabs!

Well... this isn't really a Cakewalk issue. They didn't write the forum software and people were screaming for it to be updated because the old version didn't work properly. I don't think the thread topic list is THAT much bigger with the essentials option selected but check out the Style Sheets suggestion Drew made (he's smart). I think Firefox has that capability as well (might be an add on... I've never messed with that stuff).
 
I don't really like the direction computer stuff is taking either but that's the way it goes. The kids are eating it up and they're the target demographic for pretty much everything... especially the tech.
 
Little punks. If I had a lawn they'd be getting the hose.
 

Oh and you could maybe try what sharke suggested with the Ctrl minus but set your browser or Windows control panel setting to display larger text. Might work. I used to have to Ctrl + the old version because the text was too small (as I do with many other sites). This one loads the text just right for my weary old peepers.
 

I appreciate the mobile formatting. Easier to read and post on small mobile devices is nice. Plus I'm always logged in which makes things easier.